Collie eye anomaly (CEA) is an inherited and incurable disorder of collies. It may be detected with the aid of special eye instruments at 5-8 weeks of age. It affects both eyes, and one eye may be more seriously affected than the other. Generally, the disorder does not worsen as the dog ages unless the retina detaches. Retinal detachment may occur in serious cases and usually results in blindness of that eye. Fortunately, retinal detachment does not often occur.

Affected dogs have less than normal vision, and unless very severe, it is difficult to tell by their actions. In other words, most collies with Collie Eye retain adequate functional vision. Collie Eye goes undetected in many instances.

Only selective breeding of normal animals will significantly reduce the incidence of Collie Eye. It is an autosomal recessive trait, which means that both parents must be genetic carriers of the defect for it to show up in their pups.